Our long term objective is an improved understanding of the molecular events regulating the proliferation of normal and neoplastic lymphocytes, particularly with regards to proto- oncogenes and oncogenes, respectively. In this proposal, we focus specifically on the bcl-2 (B cell lymphoma/leukemia-2) gene. The bcl-2 gene is involved in t(14;18) chromosomal translocations found in follicular lymphomas-the most common malignancy of human B cells in the United States, with over 20,000 new cases diagnosed yearly. This gene is also expressed during normal lymphocyte proliferation, suggesting a possible normal role for bcl-2 in the control of lymphocyte growth. It has never been demonstrated, however, whether bcl-2 has oncogenic potential or whether this gene can contribute to the regulation of normal cellular proliferation. We propose to explore the biological actions of bcl-2 through the use of gene transfer techniques. DNA sequences encoding bcl-2 proteins will be subcloned into several eukaryotic expression vectors, and these constructs will be introduced into several types of cell lines or cell culture systems with previously demonstrated utility for investigations of oncogenes; direct comparisons will be made with known oncogenes (myc, ras, abl). These experiments will follow three lines of investigation: 1) transfection of bcl-2 DNAs into fibroblast cells using well established assays for testing oncogenes; 2) introduction by electroporation and retroviruses of bcl-2 into established lymphoid cell lines to address issues of transformation, tumorigenicity, ability to overcome growth factor dependence, competence to respond to growth factors, and abrogation of chemically induced differentiation; and 3) retrovirus-mediated lethally irradiated mice to explore in vivo the lymphomagenic of bcl-2. In addition, we will extend our previous studies of bcl-2 in normal peripheral blood lymphocytes through the use of anti-sense synthetic oligonucleotides. These studies will assess the oncogenic and growth-regulatory activities of bcl-2 and will pave the way for future investigations of the molecular mechanisms of action of bcl-2 proteins.